Illumination indicator



Sepna, 1924. s. E. DoANE IDLUMINATION INDICATOR- Patented Sept.. 9, 1924.

SAMUEL EVERETT DOANE, OF CLEVELAND, OIIIO, ASSIGNO TO GENERAL ELECTRIC COIVIPANY, CORPORATION OF NEW YORK. y

ILLUIVIINATION INDICATOR.

, Application led March 25, 1920. Serial No. 368,720.

To all whom t may concern:`

Be it known that I, SAMUEL Evnnnr'r DoANn, a citizen of the United States, residing at Cleveland, county of Cuyahoga, State of Ohio, have `invented certain new and useful `Improvements in Illumination Indicators, of which the following is a specihcation.

My invention relates to optical devices and more particularly to devices for gauging illumination. As descriptive of its use I have called my device a visibility meter.7 My object is to produce an instrument to demonstrate the e'ect of an increase of the intensity of illumination upon increasing the speed of vision. It is more or less ditiicult to explain the value of illumination in a. manner comprehensive to the average person. Facts and iigures do not mean anything unless the auditor or reader is able to visualize their meaning. As an aid in Y the explanation oi' the advantages of illumination, I have prepared what I have called a visibility meter which may be made to serve as a gauge of illumination to the average person.. Through the use of my visibility meter, I am enabled to show the layman the desirability of higher intensities of illumination by showing the effect upon the speed of vision of an increase from a lower to a much higher intensity of il-v lumination as from 1 foot-candle to 10 footcandles. To this end I have provided a contrasting design which is presented to view for a small fraction of time iirst under the low and then under the high intensity of illumination. The greater ease with which the design is recognized under the high intensity of illumination is suiiicient to demonstrate the value thereof.

More specifically, I provide a well-known design, iigure or alphabetical letter which Acontrasts with its background as a black letter on a white card board. This black letter is placed directly under an aperture normally covered by a shutter which may be caused to move with various vspeeds across the aperture to expose the letter to view. In order to increase the fieXibility of the instrument, I provide means whereby the letter under the aperture may be readily changed at the will of the operator.

In the accompanying drawing, F ig. 1 is a bottom plan view with the back cover plate broken away; Fig. 2 is a fragmentary bottom pla-n view showing the yshutter locked in cocked position; Fig 3 is a fragmentary bottom plan. view showing the shutter just before release; Fig. 4 is a fragmentary top plan view of the aperture of the cover plate with the shutter opened to show the letter or other design; Fig. 5 is a plan view of the shutter; Fig. 6 is a plan view of the sector cooking device; and Fig. 7 is asectional detail showing the spring arm pin. n

Referring to the accompanying the designv member 10, for whichI use a white card-board disc, is rotatably pivoted at 11 on the cover plate 12 to eX- tend slightly beyond the, edge of the cover plate 12 at 13 so that the disc 10.mayvbe rotated by moving the extending portion 13 (Fig. 4). The cover plate 12 has an aperture 14 placed so that it uncovers a black letter `15 of which there area number o-n the surface of the disc 10.` p

The black letter 15 is normally covered by a shutter 16 (Fig. 5) which is rotatably pivoted to the cover plate 12 at 17 f (Figs.

drawing, prefer to 1, 2 and 3). A spring 18 fastened to the f pin 19 on the shutter 16 and to t-he arm 20 tends vto hold the shutter against the stop 21 on the cover plate 12. 'Ihe arm 2O which is pivoted on the cover plate at 22 may be used to adjust the pull exerted by the spring 18 on the shutter16 by changing the pin 23 near the handle 24- of the arm 2O fromr one to another of the series of holes 25 in the cover plate. The pin 23 is notched at .l

26 (Fig. 7) so that'when placed in a hole 25 the notch receives the cover plate and the position of the arm 20 can not be accidently changed.

The cooking sector 27 (Fig. 6), which also is pivoted at 17 (Figs. 1, 2 and 3) between the shutter 16 and the coverplate, engages the shutter 16 by means of the stops 28 and 29 to cause it tormove concentrically therewith when pressure in the direction of the arrow 30 (Fig. 2) is applied to the handle 31 ot the sector 27. The sector 27 has a segment 32 (see Figj6) which registers with the aperture 33 (see Fig. in the shutter 16 to prevent the exposure of the letter 15 through the aperture 14 oi' the cover plate when the shutteris being cocked.` When the sector 27 has been rotated to the position shownin Fig. 2, the stop 34 on the arm 36 pivoted on the cover plate at 37 and pressed towardthe stop 34 by a spring 38 resting against the arm and fastened to the cover plate.

The cooking sector is now returned toward its original position until a stop 39 (Fig. 3) on the cooking sector engages the arm 36 at the projection, which forms a side of the slot 35, and tends to force the arm 36 upward to release the shutter 16. A slot l() (see F ig. 6) in the cooking sector 27 is now registering with the aperture 1a of the cover plate. Continued pressure in the direction of the arrow Ll1 (Fig. 3) causes the shutter 16 to be released, the aperture 33 therein registering with the slot L1() of the cocking sector and the aperture 14 of the cover plate and thus exposing the letter 15 on the disc 10 as shown in Fig. 4L. The time of exposure depends upon the tension of the spring 18 which may be adjusted as previously stated. The letter on the disc 10 which is registering` with the aperture 111 is indicated on the back of the disc so as to register with an aperture 112 (Fig. 1) in the back cover plate 43 which is fastened to the cover plate 12 by the bolts lll (Fig. et) and suitably spaced therefrom by washers. 1t is obvious that the aperture t2 of the back cover plate may be used to cause the registry of a letter on the disc 10 with the aperture 14 of the cover plat-e.

1n operation the desired letter is caused to register' with the aperture 14; and a suitable tension is given to the spring 13 of the shutter 16. rlhe shutter 16 is cocked by moving the handle 31 of the coeking sector in the direction of the arrow 30 and the handle 31 returned until the stop 39 engages the arm 36 previous to the release of the shutter 16. The instrument is now ready for use. As the shutter is released and the letter exposed, the recognition of the letter by an observer is dependent upon the amount of light falling upon the letter. rThus it is easy to demonstrate the value of higher intensities in a practical way.

While l have described a specific embodimentof my invention, 1 do not wish to be limited thereto as modifications will readily suggest themselves to those skilled in the art.

lWhat 1 claim as new and desire to secure by Letters Patent of the United States, is,-

1. 1n an illumination indicator, the combination of a rotatable disc, a contrasting design on said disc, a shutter normally covering said design and having an aperture therein, a sector for engaging said shutter to bring it into a cocked position and having a slot therein normally registering with said design., a segment on said sector normally registering with said aperture, means for locking said shutter in a cocked position and means for'releasing said shutter to expose said design through said aperture for a substantially short time.

2. In an illumination indicator, the combination of a rotatable disc, a contrasting design on said disc, a shutter normally cover ing said design and having an aperture therein, a sector for engaging said shutter to bring it into a cocked position and having a slot therein normally registering with said design, a segment on said sector normally registering with said aperture, means for locking said shutter in a cocked position and means on said sector for releasing said shutter to expose said design through said aperture for a substantially short time.

3. ln an illumination indicator, the combination of a rotatable disc, a contrasting design on said disc, a shutter and having an aperture therein, means for causing said shutter to normally cover said design, a sector for engaging said shutter to bring it into a cocked position and having a slot therein normally registering with said design, a segment on said sector normally registering with said aperture, means for locking said shutter in a cocked position and means for releasing said shutter to expose said design through said aperture for a substantially short time.

1n witness whereof, I have hereunto set my hand this 23rd day of March, 1920.

sAMUEL nvrinnrr Doane. 

